It helps to know the bore size of the gun that you have.
I have several moulds.
Ringtail (or Christmas tree) bullets are preferred by many. I believe there was an example earlier in this thread attached to a paper cartridge. The driving bands are progressively larger from base to front by .010". I.E., .545", .535", .525".
Companies like N.E.I., and Rapine made molds like these in several sizes because there was a good bit of variation in bore diameters.
Not so much with the Shiloh's, but the Itialians had a good bit of variety in the bore of earlier reproductions.
The rings help center it in the bore when it's fired.
There are also Richmond Laboratories bullets available (a LEE mold, from Eras Gone). There are copies of the original Confederate design. They are/were made so that the paper cartridge was to be glued along the base of the bullet.They work very well also.
Or you can also use a round ball.
The gun can be loaded from the breech with bullet or ball with loose powder, or a paper cartridge.
There are several ways to make the paper cartridges. I prefer the flat based version but I have had good luck with all 3 methods.
Helpful videos are all over YouTube. The gentleman from Eras Gone does a good job making his videos (no, I'm not associated with him).
And to answer you question of what bullet I use, it depends on the gun. Every gun has a particular bullet that it shoots better with.